Wii Pro Logic II + AV Receiver Question

I recently purchased a Samsung HT-AS730S AV Receiver and I have a general question around the Wii's Pro Logic II functionality. My receiver has DPL IIx technology and currently I can get sound out of 5 speakers - right front, center, left front, right rear and left rear. I understand that DPL II is a 5-channel surround setup, however I was wondering if there is a way to have my sub enter in the mix. This receiver has quite a complicated setup process - so I'm hoping that I've overlooked something. Thanks in advance!

Typically the receiver takes care of sending the lower frequencies to the sub-woofer regardless of what type of audio signal or surround type. I'm not familiar with that specific model though. There are no settings on the Wii that would affect this.